Question: $ { {-5} \times \left[\begin{array}{rr}{-1} & {3} \\ {1} & {-2} \\ {4} & {4}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-5}\times{-1} & {-5}\times{3} \\ {-5}\times{1} & {-5}\times{-2} \\ {-5}\times{4} & {-5}\times{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{5} & {-15} \\ {-5} & {10} \\ {-20} & {-20}\end{array}\right]}$